1. Field of the Invention
In general, the present invention relates to clamps of the type that are commonly used by carpenters to bias pieces of wood together. More particularly, the present invention relates to auxiliary devices that attach to traditional clamps to expand the versatility of the such clamps.
2. Description of the Prior Art
Carpenters, builders, cabinet makers and other professionals that build items from wood often use clamps to temporarily hold pieces of wood together. Often objects made of wood require different pieces of wood to be glued together. Clamps are commonly used to bias glued pieces of wood together as the glue cures.
The prior art is replete with a variety of different clamps that are designed for specific purposes. It is impractical for a carpenter to have a large collection of specialty clamps available, being that the specialty clamps are rarely needed. Rather, many carpenters commonly have a collection of general purpose clamps that they adapt to different needs. One of the most common types of general purpose clamps used by carpenters is the hand screw clamp. Hand screw clamps are also commonly known as dual screw clamps and carpenters clamps.
Referring to FIG. 1, a traditional hand screw clamp 10 is shown. The hand screw clamp 10 contains two threaded shafts 12 that pass in parallel through two wooden jaw elements 14, 16. Each of the threaded shafts 12 terminate at one end with a handle 18. Each of the threaded shafts 12 engages the wooden jaw that is farthest away from the handle 18 of that threaded shaft 12. By selectively turning the threaded shafts 12, the two wooded jaws 14, 16 can be biased toward each other at a variety of different angles.
A problem associated with hand screw clamps and similarly constructed clamps, is that the threaded shafts pass between the two wooden jaws. Accordingly, a work piece can only be placed in between the wooden jaws in the areas not obstructed by the threaded shafts. This provides traditional hand screw clamps with an effective clamping range of only a few inches. Accordingly, traditional hand screw clamps are not commonly used to clamp large objects that require a clamping force to be applied several inches from the edge of that object.
In the prior art, there have been auxiliary devices invented that are intended to improve the range and versatility of different types of clamps. One such auxiliary device for a hand screw clamp is shown in U.S. Pat. No. 5,335,898 to Johnson, entitled Apparatus And Method For Clamping Structural Members During Joinder. Such a device does enable a hand screw clamp to clamp together objects otherwise not capable of being clamped by a hand screw clamp. However, to utilize the auxiliary extension, dowel holes must be drilled in the wood being clamped. Accordingly, such auxiliary attachments only have limited applications.
A need therefore exists for an auxiliary device that can be added to a clamp that significantly increases the range and versatility of the clamp without having to modify the wood being clamped. This need is met by the present invention as is described and claimed below.